Wallcoverings, typically referred to as wallpapers, decorate and protect the underlying wall surface. Such wall-coverings typically comprise a base sheet, on which an image or pattern may be printed or embossed, adhered to the wall with an adhesive. Water-based adhesives, such as wallpaper pastes, and pressure sensitive adhesives, such as those described in DeProspero, U.S. Pat. No. 5,639,539, may be used.
Wallcoverings are typically mass produced. Because only a limited number of colors and patterns can be economically mass produced, customers have a limited selection of wall-coverings from which to choose. A particular color and pattern is typically only produced for a limited period of time, so it may be difficult or impossible for a customer to obtain more wallcovering of a particular color and pattern at a later date. In addition, retailers must stock a large number of patterns. This produces high inventory carrying costs as well as losses due to inventory that is never sold. It has been estimated that 30 to 40% of all printed wallpaper is never used.
Because current production and distribution methods are most efficient when a large amount a particular color and pattern is produced, custom-designed wallcoverings tend to be expensive. In addition, the customer may be required to purchase considerably more wallcovering than is desired.
Digital imaging, particularly electrographic imaging, can potentially economically produce small amounts of custom-designed wallcoverings on demand because small amount of material can be printed economically with short turnaround times. Retailers would be able to provide customers with a much wider choice of colors and patterns. Customers could even request their own designs. With digital storage of the image, customers would be able to get an exact match of both color and pattern when reordering, even years later. Storage costs and inventory losses also would be greatly reduced. Because only the desired amount of wallcovering would be produced, it would be unnecessary for the retailer, or the customer, to store large amounts of printed wallcovering.
In electrographic imaging a latent image of electric charge is formed on a surface of an electrographic recording element, which typically comprises a dielectric layer, a conductive layer, and a base or support. The latent image is produced by imagewise deposition of electrical charge onto the surface of the dielectric layer. Typically, charged styli, arranged in linear arrays across the width of a moving dielectric surface, are used to create the latent image. Toner particles that are attracted to the charge are applied to the surface of the dielectric layer to render the latent image visible. The toned image is fixed, typically by fusing the toner particles to the element. Such processes are disclosed, for example, in Helmberger, U.S. Pat. No. 4,007,489; Doggett, U.S. Pat. No. 4,731,542; and St. John, U.S. Pat. No. 4,569,584.
A material suitable for use as a wallcovering should satisfy the standards given in "Standard Classification of Wallcovering by Durability Characteristics," ASTM Test Method F-793-93, incorporated herein by reference. In particular, the material should possess scrubability, washability, and stain and tear resistance. In addition, it should have a wet shrinkage of about 2% or less, preferably less than about 2% in the machine direction and less than about 1% in the cross-machine direction.
Willetts, U.S. Pat. No. 5,385,771, discloses an electrographic recording element suitable for the printing quality images and which can be used in pastable displays, such as billboards and wallpaper. However, it is necessary to apply paste to the backside of the element after imaging, making it inconvenient to apply the imaged element to a surface.